The present invention relates to an endoscopic tissue collecting instrument suitable for use typically in a biopsy of the liver, the pancreas or other organ by being inserted into and removed from a treatment instrument insertion channel in an endoscope.
FIG. 31 shows the distal end portion of a Menghini needle used as an endoscopic tissue collecting instrument. It comprises a rod-shaped needle shaft 10 having a pointed end 11 and a tissue retaining recess 12 formed in the lateral side of an area close to the needle end 11 and into which an excised tissue specimen is retained.
A cannula or outer sheath 20 is fitted over the needle shaft 10 to be capable of moving back and forth along the longitudinal axis and it has an annular blade 21 formed on the inner circumference of the tip for cutting off the tissue retained in the recess 12.
FIGS. 32 and 33 show how a tissue specimen for biopsy is collected with the endoscopic tissue collecting instrument. First, as shown in FIG. 32, the outer sheath 20 pierced into the tissue 100 is pulled back a little so that the desired portion of the tissue 100 is caught in the recess 12. Then, as shown in FIG. 33, the outer sheath 20 is immediately pushed forward to cut off the retained portion as a tissue specimen 101.
A problem with the above-described endoscopic tissue collecting instrument is that the depth of the tissue retaining recess 12 is inevitably much smaller than the diameter of the outer sheath 20, often causing a failure to collect an adequate amount of the tissue specimen as shown in FIG. 34
That is, as shown in FIG. 34, not all of the recess 12 is filled up with the tissue specimen 101 but some part of it remains empty as shown in FIG. 34, and thus the collected tissue specimen 101 is small in amount. Further, as shown FIG. 35, when the outer sheath 20 is being pushed forward, the tissue specimen 101 is pushed aside by the outer sheath 20 to be lifted away from the recess 12. This also causes the volume of the tissue specimen 101 that can be collected in the recess 12 to be much smaller than the capacity of the recess 12.
An object, therefore, of the present invention is to provide an endoscopic tissue collecting instrument with which an adequate amount of the tissue specimen can be easily collected without increasing the size of the instrument (for example, the diameter of the outer sheath).
The Menghini tissue collecting needle as described above is made up of a simple combination of the needle shaft 10 and the outer sheath 20, and designed for use together with a rigid endoscope.
Another problem occurs if a rigid endoscope is replaced by a soft endoscope having a flexible part to be inserted into a body cavity. Since the treatment instrument insertion channel of a soft endoscope becomes tortuous as it is passed into a body cavity, a considerably high frictional resistance in the channel makes it difficult to manipulate the needle shaft 10 and the outer sheath 20 such that they are moved back and forth in small increments and independently of each other. Hence, it has been impossible to collect the desired tissue specimen in a safe and quick manner.
Another object, therefore, of the present invention is to provide an endoscopic tissue collecting instrument that is suitable for use with both a rigid and a soft endoscope and which yet can collect the desired tissue specimen in a safe and quick manner.
According to the present invention, an aspiration channel communicating with a tissue retaining recess from the rear side is formed. The aspiration channel preferably extends between the needle shaft and the outer sheath. Therefore, a large tissue specimen can be collected by aspirating it to be retained in the recess and cutting the aspirated specimen off from the other part of the tissue. In this way, an adequate amount of the tissue specimen can be easily collected without increasing the size of the instrument.
As a further advantage, since the entire length of the aspiration channel is exposed on the surface of the needle shaft, not only the formation of the aspiration channel but also the cleaning and disinfection of it after service can be accomplished with relative ease.
In a preferred embodiment, an endoscopic tissue collecting instrument comprises a needle shaft with a tip pointed forward that has a tissue retaining recess formed in the lateral side of an area close to the tip, and an outer sheath that is fitted over the needle shaft to be capable of moving back and forth and which has a blade formed at the distal end to cut off the tissue retained in the recess. An aspiration channel communicating with the recess from the rear side is formed between the needle shaft and the outer sheath.
The aspiration channel may be formed by removing or denting part of the surface of the needle shaft. This can be accomplished by cutting or denting the shaft""s surface to a flat plane, making a groove in the surface or forming a hollow in the form of an inverted xcexa9.
Preferably, a fixing mechanism is provided to ensure that the outer sheath is fixed to the needle shaft with the needle shaft projecting by a desired length from the distal end of the outer sheath. It is also preferred that an index is provided on the side closer to the operator to tell the operator that the distal end of the outer sheath is in a specified position relative to the needle shaft.
According to the present invention, an outer needle tube, an inner needle tube and an aspirating port are provided. The tissue aspirated into the outer needle tube via the tissue aspirating port formed in its lateral side can be used as a specimen for biopsy. The collected tissue specimen has the largest size that can be expected from the given diameter of the outer needle tube. Hence, an adequate amount of the tissue specimen can be easily collected without increasing the diameter of the outer needle tube.
In addition, since the tissue specimen can be cut off by simply sliding the inner needle tube within the outer needle tube, only small sliding resistance develops and the cutting operation can be done efficiently.
In a preferred embodiment, an endoscopic tissue collecting instrument comprises an outer needle tube with a tip pointed forward that has a tissue aspirating port formed as an opening in the lateral side of an area close to the tip, an inner needle tube that is passed through the outer needle tube to be capable of moving back and forth and which has a blade formed at the distal end to cut off the tissue that has entered the tissue aspirating port, and an aspiration channel that communicates with the tissue aspirating port at the distal end and which extends to the basal ends of the outer and inner needle tubes.
If desired, the aspiration channel may be formed of the inner needle tube per se. The tissue aspirating port may be a cutout formed in the lateral side of the outer needle tube. The blade may be an annular one that is formed on the outer circumference of the inner needle tube.
The endoscopic tissue collecting instrument may be furnished with a guide tube through which the outer needle tube is passed to be capable of moving back and forth along the longitudinal axis.
According to the present invention, the basal end portion of a needle shaft is in engagement with the basal end portion of an outer sheath and a fixing member is provided that can be securely connected to or disconnected from the entrance of a treatment instrument insertion channel in an endoscope. Because of this design, the tissue specimen can be cut off by moving the outer sheath while the needle shaft that has been pierced into the tissue is securely connected to an endoscope. As a result, even in the case where the endoscopic tissue collecting instrument of the invention is passed into a tortuous treatment instrument insertion channel in a soft endoscope, the needle shaft and the outer sheath can be manipulated to move back and forth in small increments and independently of each other. Hence, the tissue collecting instrument of the invention is suitable for use with both a rigid and a soft endoscope and yet it can collect the tissue specimen in a safe and quick manner.
In a preferred embodiment, an endoscopic tissue collecting instrument comprises a needle shaft with a tip pointed forward that has a tissue retaining recess formed in the lateral side of an area close to the tip and an outer sheath that is fitted over the needle shaft to be capable of moving back and forth and which has a blade formed at the distal end to cut off the tissue retained in the recess. The basal end portion of the needle shaft is in engagement with the basal end portion of the outer sheath. A fixing member is provided, which can be securely connected to or disconnected from the entrance of a treatment instrument insertion channel in an endoscope.
The needle shaft and the outer sheath may each have flexibility. Preferably, the distal end of the needle shaft projects by a predetermined length from the exit of the treatment instrument insertion channel when the basal end portion of the needle shaft is brought into engagement with the fixing member and the fixing member is securely connected to the entrance of the treatment instrument insertion channel.
If desired, the basal end portion of the outer sheath may be capable of coming into or out of engagement with the fixing member independently of the needle shaft. The fixing member may be furnished with an urging member that pushes the outer sheath along the longitudinal axis so that the outer sheath is pushed along the longitudinal axis by the urging member if the outer sheath is brought out of engagement with the fixing member.
If desired, the area of engagement between the needle shaft and the outer sheath may be such that it can be securely connected to or disconnected from that part of the fixing member which is to be securely connected to the entrance of the treatment instrument insertion channel so that when said area is disconnected, the needle shaft and the outer sheath can be moved back and forth as an integral unit along the longitudinal axis. The endoscopic tissue collecting instrument maybe furnished with an aspiration channel that communicates with the tissue retaining recess in the distal end portion and which extends to the basal end portion of the needle shaft.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. Hei. 11-290445 (filed on Oct. 13, 1999), Hei. 11-299007 (filed on Oct. 21, 1999) and Hei. 11-306298 (filed on Oct. 28, 1999), which are expressly incorporated herein by reference in their entireties.